"Doomsday" is a pretty good episode, but it does rely on a cliché that shows up way too often on "Voyage to the Bottom of the Sea"...the disobedient crew member who cracks. Now you'd think that the ship would be manned with the best of the best. After all, it's a brand new top secret ship...the best in American know-how...yet about 1/3 of the episodes (so far) feature crew members who go nuts when time gets tough!!
The show is about Doomsday...or, Doomsday averted. The US incorrectly thinks we're under attack from the Soviets and the Seaview is ordered to fire its nuclear arsenal. However, along the way, a crew member goes nuts and then questions the morality of their mission. And, once he seems okay and the mission is canceled since it's NOT time for nuclear Armageddon, they discover they cannot disarm one of the missiles and it will go off if they surface! Yikes!!
Overall, it's compelling and worth seeing. Without the standard cliché, it would have been amazing!